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I've done a test with a fully charged (and just rebooted) phone.
Started Xiialive, listened for 10 seconds and pressed stop. I then went back to sleep, and lo and behold, 1.5 hours later the program was still using CPU. It had kept my Nexus 6 (lollipop 5.1) awake for the entire time. Normal use when doing nothing is about 2%, now 14% of the battery was gone. So in this case pressing the 'stop' button definitively did not stop the program!